The present invention concerns an electronic system including at least a first electronic device with semiconductor components comprising at least an input terminal, an output terminal, a high supply terminal brought to a high potential VDD, and a low supply terminal brought to a low potential VSS, defining a supply voltage VDD−VSS, said system allowing the electric power consumption of certain conventional electric circuits to be lowered when said system is associated therewith.
Indeed, electronic circuits with semiconductor components have in particular the peculiarity of having different operating conditions as a function of the supply voltage that is applied to them. The user of such circuits generally wishes to be able to have a sufficiently broad range of use in terms of supply voltage to prevent, in particular, the risk of abrupt variations in the supply voltage. Consequently, the common fields of use of electronic circuits with semiconductor components are often precisely delimited within the low supply voltage region, as regards the ranges corresponding to stable operating conditions.
The electronics field is constantly searching for solutions for lowering the power consumption of circuits, particularly through a drop in the minimum permissible supply voltage for said circuits to operate in a stable manner. A solution that is currently used and regularly improved consists in modifying the physical features of the semiconductor components, such as their geometry, the nature of the doping agents used or their quantity, such that the value of their threshold voltage is lowered.
FIG. 1 shows, by way of non-limiting example, a common electronic circuit, more precisely a common type of amplification circuit 100 (gain equal to 1 here) and including, in particular, semiconductor elements (not shown). Amplification circuit 100 includes, in particular, two input terminals 101 and 102, an output terminal 103 and two supply terminals i.e. one high terminal 104 and one low terminal 105. Input terminal 101 is powered by an input signal V1 whereas input terminal 102 is connected to output terminal 103 thus forming a feedback loop. Further, output terminal 103 is brought to an output potential V2. High supply terminal 104 is connected to a high potential VDD whereas low supply terminal 105 is connected to a low potential VSS.
FIG. 2 shows the behaviour of the amplification circuit or stage shown in FIG. 1 when the difference of potentials VDD−VSS is varied by applying a potential V1 of constant amplitude to input 101. The ordinate scale on the curve of FIG. 2 corresponds to the ratio V2/V1 of the output voltage over the input voltage, in other words to the gain or the transfer function H2 of the amplification stage shown in FIG. 1. It will thus be noted that gain H2, whose value is negligible for low values of the difference of potentials VDD−VSS, 201, increases rapidly from the moment when the potential difference VDD−VSS reaches a noted value VT which is the threshold voltage of the semiconductor components used in the construction of the amplification stage. The curve then defines a portion 202 constituting a transition zone in the behaviour of amplification stage 100. A last portion 203 will also be noted on the curve of gain H2 shown in FIG. 2, located after value VC1, in the zone where the value of potential difference VDD−VSS is considerably greater than VT. In this last portion 203, the value of amplification gain H2 remains substantially constant. Generally, VC1 corresponds to a value higher than 2 VT or 2.5 VT.
It can thus easily be deduced from analysing FIG. 2 that an amplification stage such as that shown in FIG. 1 can be used as an amplifier with a constant gain H2, for different supply voltage values, provided that the latter are sufficiently higher than the threshold voltage of the semiconductor components used to be at the level of portion 203.
However, the solution consisting in modifying the physical features of the semiconductors often has the drawback of making the corresponding manufacturing process much more complex and thus more expensive than conventional processes.